Carrie Underwood positively glows—and though she may have been born that way, it turns out she has a few secrets

John Shearer/WireImage; Carla Lynn

Carrie Underwood positively glows—and though she may have been born that way, it turns out she has a few secrets up her sleeve to ensure she stays that way.

At the CMAs last week, the country superstar and mom of an 8 1/2-month-old baby showed off her toned figure and rocked every single look during her 10-plus outfit changes and we wanted to know more about how she's getting it done.

So, we tapped her trainer, Erin Oprea, to give us the step-by-step lowdown on a Carrie-inspired workout.

Oprea filled us in on a fitness secret that can help mix up your routine, a workout called Tabata—which Underwood described to Shapeas her favorite workout, something she "can do at home in about a half hour.

"I'm in love with it!" the singer, who is also founder of the Calia line of fitness wear, gushed to the mag. "It's hard, but it really works. I choose seven different exercises, like squats, lunges, or push-ups, and do eight rounds of each—20 seconds on, 10 seconds off for eight rounds. It really revs up my metabolism. When I'm done, I can handle anything."

Oprea tells E! News, "Using Tabata training as a weightlifting aid has been an absolute game changer for my clients. Not only have I seen great changes in their bodies but also they have had more fun working out with this technique! It's like a bunch of tiny 20-second games, seeing how well you can do each time and trying to beat your previous round. As with all exercises, form is absolutely key here. It does no good to get a ton of reps when your body is all out of whack and you're not doing the move right!"

To begin, make sure to warm up. Oprea advises, "Five minutes will do just fine and can be a short walk, light jog, jump-roping or the classic jumping jack will do just fine."

The Nashville-based trainer, who's also a former Marine, says, "The Tabata itself is best used with a smart phone app. It will count out each round for you and play a sound when you need to start working out or when it's time to rest."

But if you don't want to have your phone with you, no problem! The basics are as follows:

• Perform the exercise for 20 seconds (go hard, you should be exhausted!)• Rest for 10 seconds• Repeat the exercise for 20 seconds (you can do one move every time or switch it up)• Do eight total rounds

"Each of the Tabatas I'm listing for you here will be 2 moves per Tabata," she adds. "Alternate between the exercises until all eight rounds are completed then move onto the next Tabata. Your body will be sore with utter joy and excitement!"

Katie Kauss

Tabata 1

Skater Hops: Squat down on your right leg, and bend your left leg behind you at a 90-degree angle. Hop into a left leg squat and bend your left leg behind you at a 90-degree angle. If you find this difficult, modify by tapping your back leg on the ground before switching directions.Squats: With your legs shoulder width apart, tilt your hips back as if you were about to sit in a chair. Lower your body until your upper legs are parallel to the floor before driving through your heels to return to the standing position.

Katie Kauss

Katie Krauss

Tabata 2

Push-Ups: Get into plank position, with your hands slightly wider than your shoulders. Lower your body close to the floor then push back to the starting position. Keep your core engaged the entire time. Lower your knees to the floor if you need to modify but make sure that the rest of your body and core stay tight and in line. Plank Jacks: Place yourself in the plank position and hold your upper body tight throughout while your legs jump wide, then back in together. Jumping jacks while holding plank! If this is too advanced, just hold the plank for a great workout.

Katie Kauss

Katie Kauss

Tabata 3

Jumping Lunges: Start in a right lunge position, with your right leg at a 90-degree angle and your left knee straight down and hovering just above the floor. Now drive through your right heel and jump up, switching foot placement in the air. Land softly and repeat. Sumo Squat With Little Jumps: Place your feet wide in a sumo squat, your toes pointing outward at a 45 degree angle. Now hop, barely leaving the ground and your form, land and repeat. They should be small but strong movements.

Katie Kauss

Katie Kauss

Tabata 4

Elbow Plank with Hip Dips: Get into a plank position, resting on your elbows. Rotate your hips downward and dip them to the left side, then back up to center. Then rotate your hips downward to the right, then back up to center. Keep the rest of your body still. To modify, if needed, perform an elbow plank throughout the round.Burpee: Jump in place and when you land, go immediately into a squat driving your hips backward. At the lowest point of your squat, place your hands on the ground so that you can drive your legs back into a quick plank before jumping back into your squat and driving upward into a jump. Repeat as you come down!

Katie Kauss

Katie Kauss

Tabata 5

Left Leg Bridge Pulse: Lie on your back, bend your right leg, and go on your right heel. Bring your left leg and hips straight up in the air and push up and down, never letting your hips hit the ground.Right Leg Bridge Pulse: Lie on your back, bend your left leg, and go on your left heel. Bring your right leg and hips straight up in the air and push up and down, never letting your hips hit the ground.

Katie Kauss

<Katie Kauss

Tabata 6

Jump Rope: This is pretty straight forward. Channel your inner elementary schooler or boxing champion and get going! If you find that your skills are currently lacking, just pretend you have a rope! I do this all the time with clients!High Knee Running in Place: Run in place making sure to bring those knees really high to get the best results.